Clark Gregg made a surprise appearance at NYCC 2012 to talk about his role as Principal Coulson on Ultimate Spider-Man, and it was here that he broke the news in person, presenting a special video message from Marvel's Joss Whedon and Kevin Feige. It was also confirmed that Joss Whedon will be co-writing the pilot with Jed Whedon and Maurissa Tancharoen.
What was not confirmed was the timeline of Marvel's S.H.I.E.L.D. TV series. It is not known if it will take place in the past, before Coulson's untimely death and the formation of The Avengers, or if it is taking place in the ongoing Marvel timeline, and is set to reveal in the pilot that Agent Coulson's so-called death was a ruse by Nick Fury to motivate his squabbling team of heroes (which has been speculated upon since the film's release this past summer). It is quite possible that we willl hear that Samuel L. Jackson is joining the ABC series in some capacity as well in the very near future.
Marvel's The Avengers was released May 4th, 2012 and stars Robert Downey Jr., Chris Evans, Mark Ruffalo, Chris Hemsworth, Scarlett Johansson, Jeremy Renner, Tom Hiddleston, Clark Gregg. The film is directed by Joss Whedon.